Grinding mill



May 13, 1930.

G. F. PETTINOS GR INDING- MILL Filed Aug. 18, 1928 3 Sheets-Sheet 1 W WW May 13, 1930. G, F 'PETT|N05 1,758,010

GRINDING MILL Filed Aug. 18, 1928 5 Sheets-Sheet v2 tkornu May`13 1930- G. F. PETTINos v 1,758,010

GRINDING MILL Filed Aug. 18, 1928 5 Sheets-Sheet 3 MM@ @www Patented May 1s,` 1930 AUNITED STATES @BINDING mn PATENT oFFIcE.

Grenen r. 'rn'rrmos or PHILADELPHIA; PENNSYLVANIA Application mea August 1s, 192s. serial N. 300,605.

This' invention relates to grinding mills, l and more particularly to the centrifugal type p progress through the v 2o Another object ofthe invention is to pref vent the passage ofthe material through the mill until it is reducedto ineness. l Y, Y

-A further object of the inventior'i iisg, 25 provide a control device lforregulating the amount of material to be groundA which is in?.

troduced into the provide a draught inducin means for with- 30 drawing the ground material from the mill,

which means wilalso. proj ect the materialby impact. l v Another object of the invention isto provide means for driving the mill at selected 35 speeds from aconstant speed prime mover.

Other objects andeatures of novelty will be apparent from the following description, as taken in connection with the accompanying drawings, in which Figure 1 is a vertical cross section thro h the improved grinding mill according to .t e present invention;

Figure'i?l is a horizontal cross section taken along the line 2 2 of Fig. 1 and showing the 45 construction of the hammers and disks; and Figure 3 is a top plan view of the grinding mill. 7

Figure 4 is a perspective view o f one of the grinding segment'swhich aref secured to the 5o hammer disks;

objects of the present inventionv isto provide a substantially continubus grind ing surfaceas a -path for the material inv a desired degree efllA constitutes the mat'erial;

Figure 5 is a section" on line 5-5 of Fig. 4; Figure 6 is a face view, and Figure 7 a sectional view showing the details of one ofthe hammers. Y i Referring more particularly to the drawings, the improved grinding mill is supported fupon a frame 1 as shownin Fig..1, which may be of any esired'construction to. aiord the necessary rigidity and strength, but-in the preferred 'form ofthe inventionshown inf this figure `it comprises La. sin le casting.

T lie frame 10 'supports Athe' casing ofthe lgrmdmgmill which comprises two shells 11 d 12, each provided 13 and 14 iving :bolts 15 byjv ameter, as indicatedi' Fig, 1, and designated` *The interior of the ,casingcomprises three stepped" cylindriealcha'mbers of varying di- 18,219 andjQO respectively.- The 'upper por! 1 tion'ofj terminates in an annular ilangggyt'wme "isbolted a cover plate 25 by means of bolts 26. v The cover plate con- .stitutfsthe top wallofthe Casing and com' prises a journal for the grinding element, and

la' means for introductionof the material to Still another object' ofthe inventionis to interposed hawaii-tile frane 1o and the casing is an annular ring .27 i having an integral tangentiallydirected spout 28 which delivery 4for the pulverized Integrally formed in the cover 25 `is an in-l let pipe 30 having rooves 31 formed in its lateral sides and a apted to receive a slide 32 for regulating the feed of material to be ound. The pipe 30 delivers to 'a conical, inwardly directed liiange l33. Also integral with the pipe30 is a lateral web 34 having a strut 35 secured thereto 'to support its outer edge. A bearing .vindicated generally at '36 is mounted in an aperture in the-web 34 and is closed by an upper cap 37.

Journaled in the bearing 36 is avertical shaft 40 which rotatably supports the grinding lelement of the machine. The lower end of the shaft is supported bya bearing 41 in turn suppprted bythe frame 10,. Keyed to face takes the form of the serrated or channeled contour shown in Fi 2.

The junction of the cyhndrical chambers 18 and 19 forms an annular shoulder 51 to which is secured, as by bolts 52, a flat annular plate 53, the upper and lower surfaces of which are provided with corrugations similar to those described for the cylinder liners. The junction of the chambers 19 and 20 forms a shoulder 54, to the underside of which is secured an annular plate similar to the plate 53, but extending further inward in proportion to its diameter. Above the liner 47, and secured to the `cover 25 as by bolts 56 is a fiat annular ring 57 having corrugations on its lower side, and fitted in the bottom of the casing just above the flange 27 is an annular ring 58 similar to the -ring 57 but inverted and of larger diameter so as to fit under the liner 49. j

Each of the disks 44, 45 and 46 carried by the shaft 40 carries a series of hammers spaced around its margin. In the form shown, the disks are formed with annular grooves 60 and 61 in their upper and lower surfaces, and the hammers are formed as segmental elements 62 and 63 respectively above and below the disks in pairs, and a bolt 64 passing through the disk and the members 62 and 63 serves to hold the parts together.

'Ihe radial faces of the hammers are preferably inclined as shown in Figure 6.

As shown in Figures 2, 4 and 5, segments 90 are fitted to the disks between the hammers, thesesegments being serrated on their outer peripheries as shown at 91. The ends of these segments are outwardly tapered or wedge-shaped as at 65 where they fit between the hammer sections, and they are locked in place by the bolts which secure the hammers to the disks. The peripheral edges of the disks are thereby protected and additional grinding surface provided. The hammers and segments provide a continuous serrated grinding surface surrounding each isk.

It will thus be noted that a substantially continuous grinding surface is provided for.

the interior of the casing. In other words, the upper hammer parts of the disk 44 coact with the rin 57, and its peripheral surface coacts with t e liner 47 while its lower hammer parts coact with the upper side of the ring 53. In like manner the upper hammers of the disk 45 coact with the lower side of the ring 53, and their ripheries coact with the liner 48 while the ower hammers coact with the upper surface of the ring 55. Similar conditions prevail in the lower chamber 20.

The rotation of the disks and hammers creates a downward draft within the casing, which assists gravity in car ing the ground material to the bottom or oor of the mill Where a pair of blades 66 sweep it out through delivery spout 28. These blades are shown attached by bolts 66 to arms on the lowest spacer member 43. The draught of air through the mill is controlled by adjustable cover plates 69, 70, on the air inlets 67, 68. The cover plates may be secured in any desired position by set screws 71, 72.

It should be noted that the plates 53, 55 and 58 extend inward definite distances inside of their respective liners 47, 48 and 49. This inward extension is so designed as to retain the material in a given chamber until the material therein has been reduced to the desired degree-of ineness for that stage of the grinding. When the desired degree of ineness is reached, the air draught is such as to float the material past the ring into the next chamber or stage. To prevent the material from passing over the hammers, I preferably provide downwardly projecting ribs or anges 53, 55, on the rlngs 53 and 55.

It is desirable to change the speed of rotation of the grinding element, either when different materials are to be ground, or to suit other conditions. At the same time, it is quite desirable to drive the machine from a constant speed shaft, in view of the popularity of alternating current motors. For this reason, a horizontal drive shaft 80 is provided, having its free end journaled in a thrust bearing 81 carried b a. ]ournal box 82 and closed by a cover 83. he driven end of the shaft is supported b a radial bearing 84 supported by a removab e plate 85 having an inner cover 86 bolted thereto. The plate 85 is bolted to the rim of a suitable aperture in the frame 10.

Keyed to the shaft 80 is a gear 87 meshing with a pinion 88 on the lower end of the shaft 40, which transmits the drive from the prime mover to the grinding element. VThe gear and pinion are covered by a housing 89 which is constructed larger than would ordinarily be necessary to house the gears, and provision is made to have these gears readily accessible so that they may be removed and another set of gears of different ratios substituted to permit the speed of the shaft 40 to be selected as desired without changing the speed of the shaft 80.

In grinding and pulverizing machines, it is very important to prevent grlt or dust from getting into the bearings, and I have therefore provided novel and efective means for .Sealing the housings of the bearings, espe- 'tering the housing. As an additional ciall ofthe shaft 40 which carriers the disks and ammers.

Referring to Figure 1, there is mounted on the upper end of the' shaft a thrower-plate 100, the rotation of which will project through discharge radially any gritty particles which come in contact'with it. This plate is just below the housing of the bearing 'bearing,r have provided'efl'ected preventive means as follows: In the lower kend of the spacer member 43 is an annular slot 104 into the which its a fixed annular rib 105 on the plate 106, these parts constituting a seal to prevent dust from the discharge chamber from entering the housing of the bearing 41. I provide also a packing ring 107 in the inner margin of the plate 106. Just below the plate 106 I provide a thrower-plate 108, the action of which is similar to that of 'the plate 100 above described. Just below the thrower-plate and above the bearin is a double seal provided by the rotating anged sleeve 109 and a fixed annular plate 110, these parts havin two complementary grooves and ribs which effectively pievent any grit getting in above the bearing 49 should it not e kept out by the thrower-plate 108." While the ritty matter is not likely to enter below earing, I provide an additional seal below the bearing', comprising arotating bellshaped art 11.1 and a fixed collar 112 which enters t e bell. The joint between the sleeve which carries the pinion88 andathelower cover of. the bearing housing is further protected by the packing ring 113.

The operationof the grinding mill isas follows :f Themateial to be ground is introduced at the spout 30 and gravitates through "the flange 33 and falls on top of the disk 44.

The rapid rotation thereof will project the material, radially against the liner 47, and the upper hammers will project some of the materialagainst the plate 57. There will, of course, be rebound back and forth, but, the

material will ultimately be drawn down to.

the plate 53 where it willbe engaged by the lower surface of the hammers. The inward- 'ly directed ilange constituted by the plate constituted by the disk 45 and the chamber 19 and their grinding surfaces.

I-Iere the material is ground to a still finer degree in the manner described for the preceding stage and is finally drawn by the draught over the inwardly directed `flange of the plate 55 and descends into the last stage constituted by the disk 46 and the chamber 20 together with their-grinding surfaces, where it is reduced to'its final form. The flanges 53a, 55" will cause the material discharging from one chamber to drop onto the 'disk in rear of the hammers in the next chamber below.

When the draught draws the material over vthe inner 'ange of the plate 58, the material descends into the chamber 27 where it is engaged by the discharge blades themselves and projected by impact out of thefspout 28,

4the draught assisting in the delivery.

Tli'e inwardly directed flanges constituted by the plates 53, 55 and 58 serve as an automatic control ofthe passa e of the material through the machine. owever, this control may be further regulated by the slide31 which may be set to limit the amount of material to be ground which is fed into the machine. At the same time, the draught produced by the rotation of the disks and hammers may be regulated by adjusting the angle of the plates 69 and 70 to provide any desired amount of air through the machine.

While one embodiment of ythe invention has been shown and described in great detail for the purposes of adequate disclosure, the broad idea of the invention is not to be limited to any of the details shown or described, but embraces such embodiments thereof as fall within the scope of the subjoined claims.

. Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In a grinding mill comprising a vertical shaft and grinding elements mounted thereon, a stepped cylindrical casing providing a plurality of compartments ofdiiferent diameters, each compartment having a cylindrical grinding surface, an inwardly projecting annlar plate forming a grinding surface at the zipper side ofthe 1egnnpartinent. and an inwardly projecting annular plate forming a grinding surface at the lower side of the compartment, certain of said plates having downwardly projecting flanges, for the purpose set forth. '1

2. In a grinding mill having a circular casing and suitable stationary grinding surfaces within said casing, a centrally arranged shaft, a disk mounted on the shaft, a series .of detachable segmental blocks mounted on the periphery of the disk, 'and means for locking said blocks rigidly to the disk.

3. In a grinding mill having a circular casing and suitable stationary grinding surfaceswithin said casing, a centrally arranged tions above and below the disk interlocked with the grooves, and means for securing said hammer sections to the disk.

5. In a grinding mill the combination with a casing having a circular lining of grinding material, of a shaft within the casing, a disk carried by the shaft, grooves in the lfaces of the disk adjacentthe margin, hammer sections above and below the disk interlocked with the grooves, and means for securing said hammer sections to the disk, said hammer sections having toothed outer faces and inclined lateral faces, for the purpose described.

6. In a grinding mill the combination with a casing havin an inner cylindrical lining, of a shaft, a isk on the shaft, aseries of grinding blocks on the periphery of the disk, said blocks having inclined faces at their ends, hammer sections above and below the disk havin Y inclined faces adapted Lto engage the incline surfaces of the blocks, and means for clamping the hammer sections and blocks removably to the disk.

7. In a grinding mill a vertically arranged cylindrical shell having outwardly and downwardly stepped compartments of increasing diameter, inwardly projecting annular plates having grindin surfaces located l above and below each of sa1d compartments and forming upper and lower grinding surfaces therefor, a central shaft, a disk carried by said shaft in each of said com artments, and hammer sections above and low said disk to cooperate respectively with the upper and lower annular grinding surfaces in the -compartment.

8. In a grinding mill, the combination with a casin provided'- with an interior grinding sur ace, of a .rotatable element within said casin havingea series of peripherally disposed ribbed'portions thereon, said ribbed portions being recessed on one side of said element at spaced eripheral points, and hammers seated in said recesses and extendinv laterally of said element, said hammers ments secured to said first named' element "peripherall thereof, said elements being recessed at t eir adjacent ends on either side of said first named element, hammers seated in said recesses and projecting laterally of said first named element on op osite sides thereof, said hammers being rib ed on the outer surface thereof to conform with said ribbed portions to rovide a continuous ribbed peripheral sur ace on said first named element.

10. In a grinding mill, the combination with a casing, of a vertically disposed rotatable shaft within said casing, a grinding element carried by said shaft and provided with a continuous eripheral grinding surface and with circum erentially spaced radial grinding surfaces above and below the element, said casing having continuous grinding surfaces opposing each of the grinding surfaces on the said element.

11. In a grinding mill, the combination with a casing provided with an interior grinding surface, of a vertically disposed rotatable element within said casing cooperating with the interior grinding surface of said casing for grinding material introduced at the upper end of the casing, a circular chamber disposed beneath said casing vfor receiving the ground material and having a delivery opening therein, a shaft for supporting said rotatable element and extendin through sa-id chamber, a bearin for sai shaft disposed beneath said c amber, a p

mediately adjacent to and on each side of said thrower plate. 4

In testimony whereof I hereunto aix my signature.

GEORGE F. PETTINOS.

being ribbed on the outer surface thereof to Y conform with said ribbed portions to provide a continuous ribbed peripheral surface on said element.

9. In a grinding mill, the combination with a casing provide with an interior grindin surface, of a rotatable element withinsai casing, a plurality of segmental ribbed. elel 

